Daily Archives: April 23, 2020

OK the 411 on the trip, and a primer on how to build a car

Things were bought, (way too much) money was spent. Legs were worn out, and my butt hurts from way too much sitting on deliberately uncomfortable benches. Not joking on that, DART was forced to buy benches that are only comfortable for the short duration so as to discourage homeless people from sleeping on them.

Now for what I bought, I had a coupon for kitchen shears for only $0.39 so I had to get a pair because our current set has gone walkabout. They work OK and did a decent job at cutting the clamshell packaging on the rest of my purchases.

I also had a coupon for a battery charger for $4, but that was a not-so-good purchase. There is a circuit that detects if there is voltage present before sending current to the terminals to prevent overloading the trickle charger, which basically turns it off if you aren’t maintaining a fully charged battery. It works great for the purpose it was built to perform, not at all for the purpose I bought it for which was to test various lights and noise makers for the Sprint-T. I had to buy a 12V power supply because the one I had also went walkabout. I guess this means another trip to buy another battery charger that wasn’t built to keep a charged battery from discharging.

The big, expensive, and hard-to-carry home part of the trip was the cordless reciprocating saw, the HF version of a Sawzall. It’s wonderful, cuts heavy steel stock like butter, and cost me roughly $120 after I bought all the extras needed to make it work, like a battery and a charger for same. Unfortunately that’s just the way things are. I needed a power tool to cut headlight buckets from a car in a junkyard, and that’s how much the cheapest tool that would do the job runs. On a brighter note I now have a tool that will do the rough cuts for the frame stock when I can get to the metal shop again.

On the subject of the Sprint-T, while I was waiting the roughly 1:40 total time between buses because of the headway change, I had the chance to think about getting to the drain plug for oil changes, when there is a belly pan in the way. I thought of various ways to remove the belly pan, and also ways to provide access without removing the pan. What I came up with as a final solution was to cut an access hole and reinforce the hole with a thicker backing piece that also functions as a flange to take the access panel as a flush fit instead of hanging underneath with overlap. Since the belly pan also substitutes for diagonal bracing the bottom of the frame any holes have to get reinforced edges so as not to be a source of failure either from fatigue or catastrophically in a wreck, this just makes the reinforcement also serve as the place the quarter-turn fasteners tie into. And as there has to be reinforcement for the hole anyway, make it do two jobs instead of just sitting there being heavy until the car gets hit.

Now I went through some variations involving hinges and magnets because I wanted something tricky for car shows and just prying against a strong magnet to open the panel instead of using a tool to turn some fasteners seemed appropriately “tricky”. But I weighed (literally) the alternatives and went with the reinforcing flange and quarter-turn fasteners over tricky hinges and magnets, especially as the T. H. and M. still had to have the reinforcing flange anyway.

Also while I was contemplating all this stuff I was thinking about fabrication for the panel that plugs the hole made to get to the drain plug. Now you may be thinking that I could just use the piece of metal I cut out to use to block the hole I just cut, and you would be Very Much Not Right. In order for the hole to not be a stress riser and cause failure in the belly pan the corners have to be radiused. The easiest way to do this is to drill holes at the corners before cutting the access which makes for some rather ugly and odd-shaped gaps when reusing the cut piece as the hatch. The solution is to use the finished hole as a template and then cut the hatch slightly oversize so that it fits flush with the rest of the skin of the belly pan. So, order of operations would be locate hole in belly pan and mark the corners, drill holes at the corners, connect holes with cuts tangent to the outside of the holes, clean up the cuts and drilled holes to have the final outline of the hole, use the hole to mark the stock for the hatch and also the stock for the reinforcement for the hatch, cut the various bits to the appropriate size and clean them up so the hatch fits flush against the edges of the hole, dimple the hatch so the fasteners also fit flush, weld the reinforcement flange to the hole, install the springs to capture the fasteners on the flange, paint, and stand back and admire. One small step among thousands of small steps would be completed.

And that’s the thing about building a car from scratch. When you look at it as a single thing it’s overwhelming, but when you look at it as a bunch of little things none of the little things is that big a deal, a day or two each to complete. Just think “Today I’m doing ‘X’, and that’s all I need to get done today” and after enough one or two-day jobs are completed you actually have a car. That’s how I have been doing it, getting the stuff together, making one thing at a time, and accumulating sub-assemblies until I have a car.